Redundancy program circuit and methods thereof

ABSTRACT

A redundancy program circuit and methods thereof. The redundancy program circuit may include a master fuse circuit with a master fuse outputting an operation enable signal to indicate a master fuse operating status, at least one control fuse circuit including at least one control fuse, the at least one control fuse circuit outputting an operating status signal for the at least one control fuse and a multiplexing unit configured to multiplex decoding address signal bits based on at least one of the operating status signal and the operation enable signal.

PRIORITY STATEMENT

This U.S. nonprovisional patent application claims priority under 35U.S.C. §119 of Korean Patent Applications 2004-50226 filed on Jun. 30,2004 and 2004-72371 filed on Sep. 10, 2004, the entire contents of whichare hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a semiconductor device andmethods thereof, and more particularly, to a redundancy program circuitand methods thereof.

2. Description of Related Art

A fabrication of a semiconductor device (e.g., a semiconductor memorydevice) may include various tests (e.g., of chips or memory devices on awafer) to verify a correct function of the semiconductor device. Forexample, such tests may verify whether circuit devices in thesemiconductor device may operate in conformity with a givenspecification or protocol. In an example test, a plurality of testparameters may be used to check electrical characteristics and/or anoperation of a tested semiconductor device. If the given test indicatesan incorrect operation of the tested semiconductor device (e.g., becausethe electrical characteristics and/or the operation of the semiconductormay not be proper), a debugging of the semiconductor device may not bepossible.

However, in an example where the semiconductor device may include adefective memory cell within a memory cell array, a repair process(e.g., debugging process) may be executed which may replace thedefective memory cell with a redundancy memory cell. In other words, ifa portion of the memory cells in the semiconductor device are defective,the defective portion of the memory cells may be replaced with at leastone spare memory cell manufactured redundantly, which may thereby enablethe semiconductor device to operate correctly.

A redundancy program circuit, which may be alternatively referred to asa fuse box or spare circuit, may be employed to achieve the abovedescribed debugging or defective memory cell replacement process. Theredundancy program circuit may employ a process which may includemelting fuses (e.g., with a high energy light, a laser, etc.), as willbe described below in greater detail with reference to FIG. 1.

FIG. 1 illustrates a block diagram of a conventional semiconductordevice 107. The conventional semiconductor device 107 may include amemory cell array 40 having a normal memory cell array 41 and a sparememory cell array 42. The normal memory cell array 41 and the sparememory cell array 42 may be connected to row decoders 20, 21, 22, 23, aspare row decoder 25, column decoders 30 and 31 and a spare columndecoder 35. Row decoders 20, 21, 22 and 23 and column decoders 30 and 31may be associated with the normal memory cell array 41, and the sparerow decoder 25 and the spare column decoder 35 may be associated withthe spare memory cell array 42.

In FIG. 1, a conventional redundancy operation may be performed by a rowspare circuit 10 and/or a column spare circuit 11, which maycollectively function as the above-described redundancy program circuit.The row spare circuit 10 may receive a pre-decoded row address DRAi froma row predecoder 6 and may generate a row redundancy enable signalX-RENi. The row redundancy enable signal X-RENi may be received by thespare row decoder 25, which may perform a debug in a row direction basedon the received row redundancy enable signal X-RENi. Likewise, thecolumn spare circuit 11 may receive a pre-decoded column address DCAi ofa column predecoder 7 and may generate a column redundancy enable signalY-RENi. The column redundancy enable signal Y-RENi may be applied to thespare column decoder 35, which may perform a debug in a column directionbased on the received column redundancy enable signal Y-RENi.

FIG. 2 illustrates an applied path of a decoding address applied to therow/column spare circuits 10/11 in the semiconductor device 107 ofFIG. 1. For example, if a 7-bit external address EADDi is applied to anaddress buffer 2, row and column internal address generators 4/5 mayeach generate an applied bit signal and a complementary signal, thecomplementary signal inverted from a logic level of corresponding bitsof the 7-bit external address EADDi, to generate a 14-bit internaladdresses IRAi and ICAi.

The row/column internal address generators 4/5 may be integrated suchthat an internal address (e.g., a row or column address) may begenerated. The row/column predecoder 6/7 may predecode the internaladdress and may generate, for example, a predecoded address having 16bits (e.g., DA01 4 bit+DA234 8 bit+DA56 4 bit). The row decoder 20 maydecode the predecoded row address DRAi and may select a given word linefrom among the word lines WL0:n of the normal memory cell array 41 andthe row spare circuit 10 may generate a row redundancy enable signalX-RENi for replacing a given row of a defective memory cell in responseto the predecoded row address DRAi.

Similarly, the column decoder 30 may decode the predecoded columnaddress DCAi, and may select a given column selection line from among aplurality of column selection lines of the normal memory cell array 41.The column spare circuit 11 may generate a column redundancy enablesignal Y-RENi for replacing a given column of a defected memory cell inresponse to the predecoded column address DCAi.

Referring to FIG. 2, lines of predecoded addresses applied to thedecoders 20/30 and the row/column spare circuits 10/11 may be dividedinto lines L1, L2 and L3. If a circuit (e.g., spare circuit 10, sparecircuit 11, etc.) with a decoder includes a NAND gate and an inverter,NMOS transistors within the NAND gate may be influenced by a bodyeffect. The body effect may cause the circuit to be unstable.

FIG. 3 illustrates the conventional row/column spare circuit 10/11 ofFIG. 1. The row/column spare circuit 10/11 may include a master fusecircuit (MFC), NMOS transistors N1-N16, a plurality of fuses F1-F16,operating enable transistors M1/M2/M3 and an AND gate AND1. A masterfuse MF may be included within the master fuse circuit MFC. The fusesF1-F16 may store addresses of a defective memory cell in order toperform a redundancy operation. In an example, the fuses F1-F16 mayinclude a silicon material (e.g., polysilicon). The fuses F1-F16 may becut (e.g., melted, cut, opened by a high energy light such as a laser,etc.). The fuses F1-F16 may be disposed in a peripheral circuit regionon a chip (e.g., row/column spare circuit 10/11).

If the normal memory cell array 41 includes a defective memory cell anda row and/or column address for designating the defective memory cell isapplied (e.g., during operation), the row spare circuit 10 and/or columnspare circuit 11 may output a redundancy enable signal RENi to disable arow and/or column of the defective memory cell and may enable a row orcolumn of a redundant memory cell (e.g., based on a cutting of the fusesF1-F16). In an example, referring to FIG. 3, if a memory cellcorresponding to an external address “0000000” is determined to bedefective (e.g., in a test process), master fuses MF and fuses F2-F4,F6-F12 and F14-F16 may be cut or blown by a fuse cutting or blowingprocess. Fuses F1, F5 and F13 may not be cut. A redundancy enable signalRENi may be outputted from an AND gate AND1 at a first logic level(e.g., a higher logic level, a lower logic level, etc.) when theexternal address is applied as “0000000”.

If a normal disable signal at a second logic level (e.g., a lower logiclevel, a higher logic level, etc.) is applied to the row/column decoder20/30, the row/column decoder 20/30 may disable a corresponding normalrow or normal column. A row or column of a defective memory cell may beset at an inoperable state (e.g., not capable of a reading or writingto/from the memory). The redundancy enable signal RENi may also beapplied to a spare row/column decoder 25/35. A row or column of thespare memory cell may be enabled and the defective memory cell may bereplaced with a redundant spare memory cell.

In other words, a defective memory cell may be replaced by cutting orblowing a master fuse among fuses MF and F1-F16 in the row/column sparecircuits 10/11 and a fuse corresponding to an address bit of thedefective memory cell.

In the above-described conventional redundancy program operation, amanufacturing yield of semiconductor devices may be increased byrepairing a defective memory cell. However, a chip size and a durationof the redundancy program operation may scale with a number of fuses.For example, if the conventional semiconductor device 107 requiresadditional memory, it may also require additional fuses for theredundancy program operation (e.g., because more bits may be needed toaddress the additional memory), thereby requiring a larger chip sizewhich may reduce a yield of the semiconductor device 107 and induce alonger duration for each defective memory cell replacement (e.g.,because multiple fuses may be cut/blown), thereby reducing a speed ofoperation.

Further, the fuses F1-F16 of FIG. 3 may be disposed corresponding toaddress bits before decoding (e.g., one fuse may be associated with eachpredecoded address bit). By disposing fuses F1-F16 as corresponding toaddress bits prior to decoding, a number of fuses in the semiconductordevice 107 may be reduced. However, the disposition of the fuses F1-F16in FIG. 3 may require that address lines be independently added (e.g.,the address lines may not be shared), which may increase a complexity ofthe conventional semiconductor device 107.

SUMMARY OF THE INVENTION

An example embodiment of the present invention is directed to aredundancy program circuit, including a master fuse circuit including amaster fuse outputting an operation enable signal to indicate a masterfuse operating status, at least one control fuse circuit including atleast one control fuse, the at least one control fuse circuit outputtingan operating status signal for the at least one control fuse and amultiplexing unit configured to multiplex decoding address signal bitsbased on at least one of the operating status signal and the operationenable signal.

Another example embodiment of the present invention is direct to aredundancy program circuit, including a master fuse circuit including amaster fuse generating an operation enable signal indicating anoperating status of the master fuse, a first fuse box circuit includingfirst program fuses disposed so as to correspond to signal bits of adecoding address and generating a first fuse box output signal inresponse to the operation enable signal, a second fuse box circuitincluding second program fuses disposed so as to correspond to signalbits of an internal address and generating a second fuse box outputsignal in response to the operation enable signal and a gating circuitfor gating the first and second fuse box output signals and generating aredundancy enable signal.

Another example embodiment of the present invention is directed to amethod of performing a redundancy program operation, includinggenerating an operation enable signal, generating at least one controlsignal pair, selectively outputting logic levels of at least a portionof a decoding address based at least in part on a first of the at leastone control signal pair and multiplexing the selectively outputted logiclevels to attain a redundancy enable signal based at least in part onthe at least one control signal pair.

Another example embodiment of the present invention is directed to amethod of performing a redundancy program operation, includinggenerating an operation enable signal, generating a first fuse boxoutput signal based on whether the operation enable signal is activated,generating a second fuse box output signal at a program fuse disposed soas to correspond to signal bits of an internal address generated beforean applied external address is decoded and gating the first and secondfuse box output signals to generate a redundancy enable signal.

Another example embodiment of the present invention is directed to amethod of reducing the number of fuses used for a redundancy programoperation, including allocating a first portion of fuses correspondingto signal bits of a decoding address and allocating a second portion offuses corresponding to signal bits of an internal address.

Another example embodiment of the present invention is directed to aredundancy program circuit, including a master fuse circuit including amaster fuse outputting an operation enable signal to indicate a masterfuse operating status, at least one control fuse circuit including atleast one control fuse, the at least one control fuse circuit outputtingan operating status signal for the at least one control fuse and adecoding circuit for decoding signal bits of a decoding address inresponse to the operating status signal and transferring a given logiclevel along with the decoding address to a decoding output terminal.

Another example embodiment of the present invention is directed to amethod of performing a redundancy program operation, includinggenerating an operation enable signal, generating an operating statussignal indicating a status of at least one control fuse and decodingsignal bits of a decoding address in response to the operating statussignal and transferring a given logic level associated with a defectivememory cell along with the decoding address to a decoding outputterminal.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of example embodiments of the invention, and areincorporated in and constitute a part of this specification. Thedrawings illustrate example embodiments of the present invention and,together with the description, serve to explain principles of thepresent invention. In the drawings:

FIG. 1 illustrates a block diagram of a conventional semiconductordevice.

FIG. 2 illustrates an applied path of a decoding address applied to therow/column spare circuits 10/11 in the conventional semiconductor deviceof FIG. 1.

FIG. 3 illustrates a conventional row/column spare circuit.

FIG. 4 is a block diagram illustrating a redundancy program circuitaccording to an example embodiment of the present invention.

FIG. 5 is a circuit diagram illustrating the redundancy program circuitof FIG. 4 according to another example embodiment of the presentinvention.

FIG. 6 is another circuit diagram illustrating the redundancy programcircuit of FIG. 4 according to another example embodiment of the presentinvention.

FIG. 7 is a block diagram illustrating a redundancy program circuitaccording to another example embodiment of the present invention.

FIG. 8 is a circuit diagram illustrating the redundancy program circuitof FIG. 7 according to another example embodiment of the presentinvention.

FIG. 9 is a circuit diagram illustrating the redundancy program circuitof FIG. 7 according to another example embodiment of the presentinvention.

FIG. 10 is a circuit diagram illustrating a redundancy program circuitaccording to another example embodiment of the present invention.

FIG. 11 is a block diagram illustrating a semiconductor memory deviceaccording to another example embodiment of the present invention.

FIG. 12 is a block diagram illustrating an example of a row/column sparecircuit according to another example embodiment of the presentinvention.

FIG. 13 is a circuit diagram illustrating the row/column spare circuitof FIG. 12 according to another example embodiment of the presentinvention.

FIG. 14 is a circuit diagram illustrating a master fuse circuitaccording to another example embodiment of the present invention.

FIG. 15 illustrates a fuse reduction example according to the exampleembodiment of FIG. 13.

FIG. 16 is a block diagram of a redundancy program circuit according toanother example embodiment of the present invention.

FIG. 17 is a circuit diagram illustrating a master fuse circuitaccording to another example embodiment of the present invention.

FIG. 18 is a circuit diagram illustrating a control fuse circuitaccording to another example embodiment of the present invention.

FIG. 19 is a circuit diagram illustrating first, second and thirddecoders and a combination circuit according to another exampleembodiment of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE PRESENT INVENTION

Hereinafter, example embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings.

In the Figures, the same reference numerals are used to denote the sameelements throughout the drawings. However, a number of transistors(e.g., NMOS transistors, PMOS transistors, etc.) are included in theFigures. It is understood that, while certain transistors in differentfigures include like numbering, the similarly named transistors may bethe same or different in example embodiments of the present invention.

FIG. 4 is a block diagram illustrating a redundancy program circuit 405according to an example embodiment of the present invention.

In the example embodiment of FIG. 4, the redundancy program circuit 405may include a master fuse circuit 200, a control fuse circuit 300,having a first control fuse 310 and a second control fuse 330, and amultiplexing circuit 400 having a first multiplexer 410 and a secondmultiplexer 430. The elements illustrated in FIG. 4 will be described infurther detail below with reference to the example embodiments of FIG. 5and FIG. 6.

FIG. 5 is a circuit diagram illustrating the redundancy program circuit405 of FIG. 4 according to another example embodiment of the presentinvention.

In the example embodiment of FIG. 5, the master fuse circuit 200 mayinclude a master fuse MF and may generate an operation enable signal ENBas a status signal that may indicate an operating status of the masterfuse MF. In an example, the operating status may be whether the masterfuse MF is cut or non-cut, where a cut status may indicate that currentmay not flow through the master fuse MF and a non-cut status mayindicate that current may flow through the master fuse MF.

In the example embodiment of FIG. 5, the master fuse circuit 200 mayinclude PMOS transistor PM1 and NMOS transistor NM1. Transistors PM1/NM1may be connected to the master fuse MF and may receive a power-up barsignal VCCHB. The master fuse circuit 200 may further include aninverter latch L1 having an input terminal connected to an outputterminal of the master fuse MF. The inverter latch L1 may includeinverters IN1, IN2 and may be connected to an output inverter IN3. Thepower-up bar signal VCCHB may be an inverted version of a power-upsignal VCCH. The power-up bar signal VCCHB may be maintained at a firstlogic level (e.g., a higher level) at an initiation of a power-upoperation. The power-up bar signal VCCHB may transition to a secondlogic level (e.g., a lower logic level) after the power-up operation.The output of the output inverter IN3 may be the operation enable signalENB.

In the example embodiment of FIG. 5, the control fuse circuit 300 mayinclude at least two control fuses F1 and F2 and may generate first toMth control signal pairs (e.g., where the Mth control pair correspondsto the Mth control fuse F1, F2, etc.) (A,/A), (B,/B), etc. as a statussignal indicating an operating status of each corresponding control fuseF1, F2 (e.g., where the operating status is whether the fuse F1 and/orF2 may be cut or non-cut), where M is a natural number greater than orequal to 2.

In the example embodiment of FIG. 5, the first control fuse 310 mayinclude PMOS transistor PM2 and NMOS transistor NM2. Transistors PM2/NM2may be connected to the control fuse F1 and may receive the power-up barsignal VCCHB. The first control fuse 310 may further include an inverterlatch L2 having an input terminal connected to an output terminal of thecontrol fuse F1. The inverter latch L2 may include inverters IN4 and IN5and may be connected to an output NOR gate NOR1.

In the example embodiment of FIG. 5, the second control fuse 330 mayinclude PMOS transistor PM3 and NMOS transistor NM3. Transistors PM3/NM3may be connected to the control fuse F2 and may receive the power-up barsignal VCCHB. The second control fuse 330 may further include aninverter latch L3 having an input terminal connected to an outputterminal of the control fuse F2. The inverter latch L3 may includeinverters IN6 and IN7 and may be connected to an output inverter IN8.

In the example embodiment of FIG. 5, the first multiplexer 410 mayinclude NMOS transistors M1-M4. The first multiplexer 410 may outputgiven logic levels (e.g., the first logic level, the second logic level,etc.) of signal bit portions (e.g., DA01<0>, DA01<3>) among signal bits(e.g., DA01<0>, DA01<1>, DA01<2>, DA01<3>) of a decoding address appliedin units of 2n bits, where n is a natural number greater than or equalto 2, to output terminals OU1 and OU2 provided by the numbercorresponding to the signal bit portions, in response to a correspondingcontrol signal pair (e.g., control signal pair A,/A) from among thefirst to Mth control signal pairs.

In the example embodiment of FIG. 5, the second multiplexer 430 mayinclude NMOS transistors M5 and M6. The second multiplexer 430 mayoperate (e.g., become enabled) when an operation enable transistor 450is turned off. When the operation enable signal ENB is activated (e.g.,set to the second logic level), the second multiplexer 430 may perform asubordinate half-reduction for the signal bit portion, received fromoutput terminals of the first multiplexer 410, in response to controlsignal pairs (e.g., control signal pair B,/B) that may not be applied tothe first multiplexer 410 when the operation enable signal ENB isactivated (e.g., set to the second logic level). The second multiplexer430 may thereby transfer a given logic level (e.g., one of the first andsecond logic levels, which may correspond to a single bit) to a programoutput terminal FO1.

Hereafter, for purposes of explanation, a given terminal receiving asignal bit (e.g., DA01<0>) of a decoding address to perform a redundancyoperation, may be referred to as a first output terminal. In an example,the first output terminal may correspond to the output terminal OU1 andother output terminals may be separated from the program output terminalFO1.

In another example embodiment of the present invention, during aredundancy operation, referring to the second multiplexer 430, only agiven logic level of the first output terminal (e.g., output terminalOU1) may be transferred to the program output terminal FO1. Other outputterminals (e.g., output terminal OU2) may be separated from the programoutput terminal FO1.

In another example embodiment of the present invention, referring toFIG. 5, if signal bits (DA01<0>, DA01<1>, DA01<2>, DA01<3>) of thedecoding address include 4 bits (e.g., as shown in FIG. 5), an output ofthe multiplexing circuit 400, set to the first logic level, may besupplied to the program output terminal FO1. For example, if an addressof a defective memory cell among normal memory cells is (00), the masterfuse MF and the control fuses F1 and F2 may be cut (e.g., by a laserbeam). The redundancy program may thereby be executed by a cuttingoperation.

In another example, referring to FIG. 5, after receiving a shipment ofrepaired semiconductor memory devices (e.g., repaired through aredundancy operation), an address (e.g., address (00)) indicating anaddress of defective memory cell may be applied in a normal operationstate such that signal bits (DA01<0>, DA01<1>, DA01<2>, DA01<3>) of adecoding address may correspond to (00, 01, 10, 11), respectively, theoperation enable signal ENB may be generated at the second logic level,the control signal pair A,/A may be generated at the first logic leveland the second logic level, respectively, the control signal pair B,/Bmay be generated at the first logic level and the second logic level,respectively. The operation enable signal ENB may be set to the secondlogic level because NMOS transistor NM1 may be turned on when thepower-up bar signal VCCHB is applied at the first logic level such thatthe master fuse MF may be cut.

An output EN of the inverter latch L1 may transition to the first logiclevel and the operation enable signal ENB (e.g., the output of theoutput inverter IN3) may transition to the second logic level. When thepower-up bar signal VCCHB transitions to the second logic level, theNMOS transistor NM1 may be turned off and the output EN of the inverterlatch L1 may be maintained at the first logic level. The power-up barsignal VCCHB and the operation enable signal ENB may be maintained atthe second logic level for a given period of time.

In another example, if the outputs control signal A and /A of thecontrol signal pair A,/A are set to the first logic level and the secondlogic level, respectively, the NMOS transistor NM1 may be turned on whenthe power-up bar signal VCCHB is applied at the first logic level suchthat the control fuse F1 may be cut. The control signal A (e.g., of thecontrol signal pair A,/A) of the inverter latch L2 may transition to thefirst logic level, and the control signal /A of NOR gate NOR1 (e.g., forNOR-gating the operation enable signal ENB and the control signal A) maytransition to the second logic level. When the power-up bar signal VCCHBtransitions to the second logic level, the NMOS transistor NM1 may beturned off and the control signal A of the inverter latch L2 may bemaintained at the first logic level. Thus, the power-up bar signal VCCHBand the control signals A and /A of the control signal pair A,/A may bemaintained at their respective logic levels for a given period of time.

Further, in another example, if the control signals B and /B of thecontrol signal pair B,/B are generated at the first logic level and thesecond logic level, respectively, the operation of the second controlfuse 330 may be similar as the above-described example with respect tofirst control fuse 310 where the control signals A and /A of the controlsignal pair A,/A are set to the first and second logic levels,respectively.

In another example, if the operation enable signal ENB is activated, thecontrol signal pair A,/A and the control signal pair B,/B may transitionto the second logic level, the first logic level, the second logiclevel, the first logic level and the second logic level, respectively,the operation enable transistor 450 may be turned off, transistors M1and M4 of the first multiplexer 410 may be turned on, and a transistorM5 of second multiplexer 430 may be turned on. The redundancy enablesignal RENi may transition to the first logic level and may be outputtedto the program output terminal F01. The redundancy enable signal RENimay correspond to the signal bit DA01<0> of the decoding address, forexample, the address (00). A redundancy operation may be performed forthe address (00) by cutting the master fuse MF and the control fuses F1and F2, (e.g., when the redundancy enable signal RENi may be activatedwhen an address of (00) may be applied in a normal operation of asemiconductor device (e.g., a semiconductor memory device)) therebydebugging or correcting operation for a semiconductor device includingthe redundancy program circuit 405.

Alternatively, in another example, if a redundancy operation isperformed for address (01), a signal bit DA01<1> of the decoding addressmay correspond to address (01) and the master fuse MF and the controlfuse F2 may be cut. In another alternative example, if a redundancyoperation is performed for address (10), a signal bit DA01<1> of thedecoding address may correspond to address (10) and the master fuse MFmay be cut. In another alternative example, if a redundancy operation isperformed for address (11), a signal bit DA01<1> of the decoding addressmay correspond to address (11) and the master fuse MF and the controlfuse F1 may be cut.

In another example embodiment of the present invention, referring toFIG. 5, a redundancy operation may be performed with multiplexers whichmay control a plurality of fuses numbering less than a number of addressbits (e.g., of a decoding address).

FIG. 6 is a circuit diagram illustrating the redundancy program circuit405 of FIG. 4 according to another example embodiment of the presentinvention.

In an example, in contrast to FIG. 5 where first and second controlfuses 310/330 may be included based on the decoding address having 4bits, FIG. 6 illustrates seven control fuses (e.g., 310, 330, 311, 331,332, 312, 333, etc.) based on the decoding address having 16 bits.

In an alternative example embodiment of the present invention, if signalbits of a decoding address are increased to 16 bits, a redundancycontrol circuit (e.g., redundancy program circuit 405) may include ahigher number of control fuses (e.g., seven) and a number ofmultiplexers.

In the example embodiment of FIG. 6, the second multiplexer 430 of FIG.5 may be one of a plurality of multiplexers corresponding to programoutput terminals FO1, FO2 and FO3, respectively, the outputs of whichmay be received by an AND gate 500. The output of the AND gate 500 maybe the redundancy enable signal RENi.

In the example embodiment of FIG. 6, the redundancy program circuit 405may include a total of eight fuses (e.g., including one master fuse MFand seven control fuses 310/311/312/330/331/332/333). Thus, fewercontrol fuses than decoding address bits may be used for a redundancyoperation.

In another example embodiment of the present invention, control fusesmay be installed within control fuse circuit 300 and the redundancyenable signal RENi may be generated with a multiplexing operation. Theabove-described example embodiment may allow a reduction (e.g., ahalf-reduction) for signal bits of the decoding address and the numberof fuses used for a redundancy program may thereby be reduced. Thereduced number of fuses may reduce a chip size. Further, a number ofcutting operations may be reduced by the reduction of the number offuses, thereby increasing an efficiency and speed of a redundancyoperation (e.g., a repair or debugging time for semiconductor devicesincluding the redundancy program circuit 405).

FIG. 7 is a block diagram illustrating a redundancy program circuit 700according to another example embodiment of the present invention.

In the example embodiment of FIG. 7, the redundancy program circuit mayinclude the master fuse circuit 200 (e.g., as above-described withrespect to FIGS. 4-6), the control fuse circuit 300 (e.g., asabove-described with respect to FIGS. 4-6), a multiplexer 420 and aprogram fuse circuit 440. The elements illustrated in FIG. 7 will bedescribed in further detail below with reference to the exampleembodiments of FIG. 8 and FIG. 9.

FIG. 8 is a circuit diagram illustrating the redundancy program circuit700 of FIG. 7 according to another example embodiment of the presentinvention.

In the example embodiment of FIG. 8, the master fuse circuit 200 mayfunction as the master fuse circuit 200 as described above with respectto FIG. 5. The control fuse circuit 300 may function as the firstcontrol fuse 310 in the control fuse circuit 300 of FIG. 5. Themultiplexer 420 may function as the first multiplexer 410 of FIG. 5.Thus, the descriptions of master fuse circuit 200, control fuse circuit300 and multiplexer 420 are omitted in the description of the exampleembodiment of FIG. 8 for the sake of brevity.

In the example embodiment of FIG. 8, the program fuse circuit 440 mayinclude program fuses FU1 and FU2. The program fuse circuit 440 mayoperate (e.g., become enabled) when an operation enable transistor 450is turned off. When the operation enable signal ENB is activated (e.g.,transitions to the second logic level) the program fuse circuit 440 maytransition to the logic level associated with a given bit (e.g.,DA01<0>) based on at least one programmed fuse (e.g., a non-cutting ofFU1 and a cutting of FU2) among fuses FU1 and FU2 connected tocorresponding to output terminals OU1 and OU2, respectively, of themultiplexer 420. The output of the program fuse circuit 440 may bereceived by the program output terminal FO1.

In another example embodiment of the present invention, the program fusecircuit 440 may transfer a logic level received from the first outputterminal OU1 to the program output terminal FO1 through fuse FU1connected to the first output terminal OU1. The output terminal OU2 maynot operatively connected to the program output terminal FO1 because ofa cutting of fuse FU2 which may be connected to at least one outputterminal OU2 that may be independent or separate from the first outputterminal OU1. In an alternative example, the fuse FU2 may be non-cut andthe fuse FU1 may be cut (e.g., based on another received signal bit forthe redundancy operation).

In the example embodiment of FIG. 8, when signal bits (DA01<0>, DA01<1>,DA01<2>, DA01<3>) of the decoding address include 4 bits, the redundancyenable signal RENi may be set to the first logic level and may beoutputted to the program output terminal FO1. For example, if an addressof a defective memory cell is address (00), the master fuse MF, thecontrol fuse F1 and the program fuse FU2 may be cut (e.g., by a laserbeam) to perform a redundancy operation.

In another example, signal bits (DA01<0>, DA01<1>, DA01<2>, DA01<3>) maycorrespond to (00, 01, 10, 11), respectively. In a further example, theredundancy enable signal RENi may correspond to the signal bit DA01<0>of the decoding address, for example, the address (00). A redundancyoperation may be performed at address (00) by cutting the master fuseMF, the control fuse F1, and the program fuse FU2 when the redundancyenable signal RENi is activated for the address (00) (e.g., when theaddress (00) may be applied in a normal operation of a semiconductordevice (e.g., a semiconductor memory device)), thereby debugging orcorrecting operation for the semiconductor device.

Alternatively, in another example, the redundancy enable signal RENi maycorrespond to the signal bit DA01<1> of the decoding address, forexample, the address (01). A signal bit DA01<1> of the decoding addressmay correspond to address (01) and the master fuse MF and the programfuse FU2 may be cut. In another alternative example, the redundancyenable signal RENi may correspond to the signal bit DA01<2> of thedecoding address, for example, the address (10). A signal bit DA01<2> ofthe decoding address may correspond to address (10) and the master fuseMF and the program fuse FU1 may be cut. In another alternative example,the redundancy enable signal RENi may correspond to the signal bitDA01<3> of the decoding address, for example, the address (11). A signalbit DA01<3> of the decoding address may correspond to address (11) andthe master fuse MF, the control fuse F1, and the program fuse FU1 may becut.

In another example embodiment of FIG. 8, an address (00) may indicate anaddress of a defective memory cell and may be applied during normaloperation of a semiconductor device. Signal bits (DA01<0>, DA01<1>,DA01<2>, DA01<3>) of a decoding address may correspond to (00, 01, 10and 11), respectively. The operation enable signal ENB may be generatedat the second logic level, and a control signal pair A,/A may begenerated such that control signal A may be at the first logic level andcontrol signal /A may be at the second logic level.

The operation enable transistor 450 may be turned off, transistors M1and M4 of multiplexer 420 may be turned on, and the program fuse FU1 maynot be cut. Thus, the redundancy enable signal RENi may be output at thefirst logic level to the program output terminal FO1. The receivedredundancy enable signal RENi may correspond to a signal bit DA01<0> ofthe decoding address, which may the address (00). A redundancy operationmay be required to debug a semiconductor device by cutting the masterfuse MF, the control fuses F1 and the program fuse FU1 (e.g., when anaddress (00) of a defective memory cell may be applied during operationof a semiconductor device).

In another example embodiment of FIG. 8, an address of a defectivememory cell may be the address (01). In this example, a redundancyoperation may cut the master fuse MF and the program fuse FU2 to debugthe semiconductor device.

In another example embodiment of FIG. 8, an address of a defectivememory cell may be the address (10). In this example, a redundancyoperation may cut the master fuse MF and the program fuse FU1 to debugthe semiconductor device.

In another example embodiment of FIG. 8, an address of a defectivememory cell may be the address (11). In this example, a redundancyoperation may cut the master fuse MF, the fuse F1 and the program fuseFU1 to debug the semiconductor device.

In another example embodiment of FIG. 8, a redundancy program may beperformed such that a multiplexing operation may be executed which maythereby control signal bits of a decoding row address and/or decodingcolumn address, thereby reducing a number of use fuses and shortening aduration of a redundancy operation (e.g., as compared to a conventionalredundancy operation).

FIG. 9 is a circuit diagram illustrating the redundancy program circuit700 of FIG. 7 according to another example embodiment of the presentinvention.

In contrast to the example embodiment of FIG. 8 where the number offuses may be four (one master fuse MF, one control fuse F1, and twoprogram fuses FU1, FU2) if signal bits of the decoding address mayinclude 4 bits, FIG. 9 illustrates another example embodiment of thepresent invention where the number of fuses may be reduced when signalbits of the decoding address are increased.

In the example embodiment of FIG. 9, if signal bits of a decodingaddress increase to 16 bits, the redundancy program circuit 900 mayinclude twelve fuses, with one master fuse MF, three control fuses, andeight program fuses (e.g., FU1-FU8).

FIG. 10 is a circuit diagram illustrating a redundancy program circuit1000 according to another example embodiment of the present invention.

In the example embodiment of FIG. 10, the redundancy program circuit1000 may include the master fuse circuit 200 and control fuses 310, 312,313, 314 and 315, through which signal bits (DA01<0>, DA01<1>, DA01<2>,DA01<3>) of the decoding address and signal bits (DA56<0>, DA56<1>,DA56<2>, DA56<3>) of the decoding address may be multiplexed andoutputted through the program output terminals FO1 and FO3. Signal bits(DA234<0>-DA234<7>) of the decoding address may be multiplexed andoutputted through the program output terminal FO2, and control signalpairs B,/B, C,/C and D,/D may be applied to multiplexers. Logic levels(e.g., the first logic level, the second logic level, etc.) at theterminals FO1, FO2 and FO3 may be gated by the AND gate 500. The ANDgate 500 may output the redundancy enable signal RENi.

In the example embodiment of FIG. 10, the redundancy program circuit1000 may include a total of ten fuses (e.g., a master fuse and ninefuses).

FIG. 11 is a block diagram illustrating a semiconductor memory device1100 according to another example embodiment of the present invention.

In the example embodiment of FIG. 11, the semiconductor device 1100 maygenerally function similar to the conventional semiconductor device 107of FIG. 1. However, the semiconductor device 1100 of FIG. 11 may includea row spare circuit 10 a and a column spare circuit 11 a, which maydiffer in function as compared to the row spare circuit 10 and thecolumn spare circuit 11 of FIG. 1.

In the example embodiment of FIG. 11, a portion of signal bits of adecoded address of the row predecoder 6 (e.g., the output of rowpredecoder 6) may be transferred to an input line LI1 and thereby to therow spare circuit 10 a. A portion of signal bits of an internal addressoutputted from the row internal address generator 4 (e.g., the input ofrow predecoder 6) may be transferred to an input line LI2 and thereby tothe row spare circuit 10 a.

In the example embodiment of FIG. 11, a portion of signal bits of adecoded address of the column predecoder 7 (e.g., the output of columnpredecoder 7) may be transferred to the column spare circuit 11 a. Aportion of signal bits of an internal address outputted from the columninternal address generator 5 (e.g., the input of column predecoder 7)may be received by the column spare circuit 11 a.

In the example embodiment of FIG. 11, fuses may be disposed in aone-to-one ratio with respect to the decoded address bits. Fuses mayalso be disposed corresponding to the portion of address bits beforedecoding.

FIG. 12 is a block diagram illustrating an example of the row/columnspare circuit 10 a/11 a of FIG. 11 according to another exampleembodiment of the present invention.

FIG. 13 is a circuit diagram illustrating the row/column spare circuit10 a/11 a of FIG. 12 according to another example embodiment of thepresent invention.

In the example embodiment of FIGS. 12 and 13, the row/column sparecircuit 10 a/11 a may include a master fuse circuit 90 for generatingoperation enable signals EN and ENB. The row/column spare circuit 10a/11 a will be described in greater detail later with respect to FIG.14. The row/column spare circuit 10 a/11 a may further include firstfuse box circuits 92/94, second fuse box circuits 100/110/120 and agating circuit 130.

FIG. 14 is a circuit diagram illustrating the master fuse circuit 90 ofFIG. 12 according to another example embodiment of the presentinvention. Master fuse circuit 90 may include PMOS transistor PM14 andNMOS transistor NM14 which may each be connected to the master fuse MF.The transistors PM14 and NM14 may receive the power-up bar signal VCCHB.Master fuse circuit 90 may further include an inverter latch L14 whichmay include inverters IN141 and IN142. The mater fuse circuit 90 mayfurther include an output inverter IN143.

In the example embodiment of FIGS. 12 and 13, the first fuse boxcircuits 92 and 94 may include program fuses disposed corresponding torespective decoding signal bits DA01<0:3> and DA56<0:3. First fuse boxcircuits 92 and 94 may generate first fuse box output signals FO01 andFO56, respectively, in response to the operation enable signals EN/ENB.

In the example embodiment of FIGS. 12 and 13, the second fuse boxcircuits 100, 110 and 120 may include program fuses disposedcorresponding to signal bits of an internal address IADD<2>, IADD<3> andIADD<4> which may be generated before an applied external address may bedecoded. Second fuse box circuits 100/110/120 may generate a second fusebox output signal FO2, FO3 and FO4, respectively in response to theoperation enable signals EN/ENB.

In the example embodiment of FIG. 12, the gating circuit 130 may gate(e.g., AND gate) the first and second fuse box output signals FO01,FO56, FO2, FO3 and FO4, and may generate the redundancy enable signalRENi.

In the example embodiment of FIG. 13, the first fuse box circuit 92 mayinclude NMOS transistors N1-N4, program fuses F1-F4 connected to sourceterminals of the NMOS transistors N1-N4, and an operation enable NMOStransistor M1.

In the example embodiment of FIG. 13, the first fuse box circuit 94 mayinclude NMOS transistors N5-N8, program fuses F5-F8 connected to sourceterminals of the NMOS transistors N5-N8 and an operation enable NMOStransistor M2.

In the example embodiment of FIG. 13, the second fuse box circuit 100may include a program fuse F9, inverters IN131/IN132 and NMOStransistors N9-N16. The second fuse box circuit 120 may include aprogram fuse F11, inverters IN135/IN136 and NMOS transistors N25-N32.

In the example embodiment of FIG. 13, the gating circuit 130 may includeNAND gates NAN1/NAN2 and a NOR gate NOR1.

An example of a redundancy program operation for the second fuse boxcircuit 100 of FIGS. 13 will now be described.

In the example operation of FIG. 13, a node ND1 may be maintained as thesecond logic level at a power-up initial operation. If the program fuseF9 is not cut, a logic level of the node ND1 may transition to the firstlogic level (e.g., power source voltage VDD applied through the fuse F9,an external power source voltage, etc.). The NMOS transistors N10 andN12 may be turned on and the NMOS transistors N13 and N16 may be turnedoff. A source terminal of the NMOS transistor N12 may be connected to aprogram output terminal FO2. An input logic of signal bit IADD<2> of aninternal address may pass through transistor N10, transistor N12 andprogram output terminal FO2, and may be applied as an input of the NANDgate NAN2.

Alternatively, if the fuse F9 is cut, the input logic of signal bitIADD<2> may be cut off (e.g., the logic level may be the second logiclevel irrespective of the logic level of the signal bit IADD<2>). Asignal path through transistor N11, transistor N13 and program outputterminal FO2 may be activated and the signal bit IADD<2> of an internaladdress inverted by inverter IN1 may be applied as an input of the NANDgate NAN2.

In the example embodiment of FIG. 13, the row/column spare circuit 10a/11 a may include twelve fuses.

FIG. 15 illustrates a fuse reduction example according to the exampleembodiment of FIG. 13.

In the example embodiment of FIG. 15, eleven fuses (e.g., not countingthe master fuse MF) may be included in the row/column spare circuit 10a/11 a. As discussed in the background of the invention, theconventional row/column spare circuit 10/11 may include sixteen fuses.

In the example embodiment of FIG. 15, the convention row/column sparecircuits 10/11 may each take up space SI and the row/column sparecircuits 10 a/11 a may each take up space S2 on a semiconductor chip.Extra space S3 may indicate a “saved” amount of space by employment ofthe row/column spare circuits 10 a/11 a in place of the conventionalrow/column spare circuits 10/11. The extra space S3 may be provided byremoving fuses F12-F16 of the row/column spare circuit 10/11. Thereduced chip size may reduce a layout size and/or a repair time of asemiconductor device (e.g., semiconductor device 1100).

FIG. 16 is a block diagram of a redundancy program circuit 1600according to another example embodiment of the present invention. Theredundancy program circuit 1600 illustrates an example where thedecoding address may include 16 bits.

In the example embodiment of FIG. 16, the redundancy program circuit1600 may include a number of fuses corresponding to a number of bits inan external address or an internal address. In contrast, theconventional row/column spare circuit 10/11 of FIG. 1 may include a fusefor each signal bit of the decoding address. In an example, if aninternal address includes 3 bits and a decoded or decoding addressincludes 8 bits, the conventional row/column spare circuit 10/11 mayinclude 8 fuses. In contrast, in the above-example, the redundancyprogram circuit 1600 according to an example embodiment of the presentinvention may include 3 fuses.

In the example embodiment of FIG. 16, the redundancy program circuit1600 may include a master fuse circuit 210, a plurality of control fusecircuits 311-317, a combination circuit 500, first decoder 411, a seconddecoder 412 and a third decoder 413.

In the example embodiment of FIG. 16, the master fuse circuit 210 mayinclude a master fuse MF and may generate operation enable signalsEN/ENB to indicate an operating status (e.g., whether the master fuse MFis cut or non-cut) of the master fuse MF.

FIG. 17 is a circuit diagram illustrating the master fuse circuit 210 ofFIG. 16 according to another example embodiment of the presentinvention.

In the example embodiment of FIG. 17, the master fuse circuit 210 mayinclude PMOS transistor PM17, NMOS transistors NM171/NM172 and inverterINV17. If the power-up bar signal VCCHB is applied at the first logiclevel and the master fuse MF is cut, the NMOS transistor NM171 may beturned on. An operation enable signal ENB of inverter INV17 maytransition to the first logic level and an operation enable signal ENmay transition to the second logic level. If the power-up bar signalVCCHB transitions to the second logic level, the NMOS transistor NM171may be turned off and the output EN may be maintained at the secondlogic level (e.g., by a transition to the first logic level of the NMOStransistor NM172). Thus, the power-up bar signal VCCHB and the operationenable signal EN may be maintained at the second logic level.

In the example embodiment of FIG. 16, control fuse circuits 311-317 maybe controlled based on an operation enable signal (e.g., EN, ENB, etc.)of the master fuse circuit 210, and may include a plurality of controlfuses AF which may generate first to Mth control signal pairs (e.g., Mbeing a natural number greater than or equal to 2) as status signalsthat may indicate an operating status cutting of the control fuses(e.g., whether a given control fuse is cut or non-cut) based on memorycell defect information. In an example, a given number of control fusesAF may correspond to the bit number of an address signal (e.g., aninternal address signal, an external address signal, etc.).

FIG. 18 is a circuit diagram illustrating the control fuse circuit 311of FIG. 16 according to another example embodiment of the presentinvention.

In the example embodiment of FIG. 18, if the power-up bar signal VCCHBis applied at the first logic level and the control fuse AF is cut, NMOStransistor NM181 may be turned on. An output Ai of inverter INV18 maytransition to the first logic level, and an output AiB from a pass gatePG1 may transition to the second logic level. If the power-up bar signalVCCHB transitions to the second logic level, the NMOS transistor NM181may be turned off and a node NO2 may be maintained at the second logiclevel (e.g., based on an on-transition of the NMOS transistor NM182).Thus, the power-up bar signal VCCHB and the control signal AiB may bemaintained at the second logic level and the control signal pair Ai maybe maintained at the first logic level.

FIG. 19 is a circuit diagram illustrating the first, second and thirddecoders 411/412/413 and the combination circuit 500 of FIG. 16according to another example embodiment of the present invention.

In the example embodiment of FIG. 19, first, second and third decoders411/412/413 (e.g., which may include at least one NMOS transistor) mayeach output a given bit at a given logic level (e.g., the first logiclevel, the second logic level, etc.) from among decoding address signalbits each applied in a unit of 2m bit, to the program output terminalsFO1, FO2, FO3, in response to combinational logic inputs ofcorresponding control signal pairs among the first to Mth control signalpairs.

In the example embodiment of FIG. 19, the first decoder 411 may includeunit decoders DA01<0>-DA01<3> which may perform a redundancy decoding ofa 4 bit decoding address. Each of the unit decoders may include NMOStransistors (e.g., NMOS transistors N1 and N2 in DA01<0>, etc.), whosechannels may be connected in series and may be controlled by acombinational logic input (e.g., a 2 bit combinational logic input).

In the example embodiment of FIG. 19, the second decoder 412 may includeunit decoders da234<0>-DA234<7> which may perform a redundancy decodingof an 8 bit decoding address. Each of the unit decoders may include NMOStransistors (e.g., NMOS transistors N1, N2 and N3 in DA234<0>), whosechannels may be connected in series and may be controlled by acombinational logic input (e.g., a 3 bit combinational logic input).

In the example embodiment of FIG. 19, the third decoder 413 may beconstructed and function similarly to the first decoder 411 (describedabove).

In the example embodiment of FIG. 19, the combination circuit 500 may bethe AND gate 500 and may perform an AND operation on signals receivedfrom the program output terminals FO1/FO2/FO3, the output of which maybe the redundancy enable signal RENi. In other example embodiments, thecombination circuit 500 may include other combinational logic structures(e.g., an AND gate, a NOR gate, a NAND gate, etc.).

In the example embodiment of FIG. 19, fuses may not be included in thefirst/second/third decoders 411/412/413. Further, the first to Mthcontrol signal pairs generated by the memory cell defect information maybe include only one fuse per address bit (e.g., internal address bit,external address bit, etc.).

An example of operation will now be described with reference to FIG. 19.In the following example, it may be assumed that an internal or externaladdress may have 7 bits and a redundancy enable address including bits(A6, A5, A4, A3, A2, A1, A0) may correspond to address (1111100),respectively.

In the example operation of FIG. 19, control fuses other than controlfuses corresponding to address bits A0 and A1 (e.g., the master fuse MFand the control fuses 311 to 317) may be cut. A0B and A1B may be set tothe first logic level by the first decoder 411. Address bits A2, A3 andA4 may be set to the first logic level and may be received by the seconddecoder 412. Address bits A5 and A6 may be set to the first logic leveland may be received by the third decoder 413. The address (1111100) maybe received from an external source/device and may be decoded at anaddress decoder to generate decoded addresses DA01<0:3>, DA234<0:7> andDA56<0:3>. The generated decoding address signals may be received asDA01<0:3> at the first logic level (e.g., a higher logic level) at thefirst decoder 411, DA234<0:7> at the first logic level (e.g., a higherlogic level) at the second decoder 412 and DA56<0:3> at the first logiclevel (e.g., a higher logic level) at the third decoder 413. Allremainder decoded address may be at a second logic level (e.g., a lowerlogic level).

In the above-described example method of FIG. 19, the unit decodercorresponding to the decoding address DA01<0> (e.g., including NMOStransistors N1 and N2) of the first decoder 411 may be turned on oractivated in response to the corresponding combination logic levels(e.g., A0B and A1B), and the activated first logic level of the DRA01<0>may be transferred to the program output terminal FO1. In the seconddecoder 412, the unit decoder corresponding to the decoded addressDA234<7> (e.g., including NMOS transistors N70/N71/N72) may be turned onor activated in response to the corresponding combination logic levels(e.g., A2, A3,and A4), and the activated first logic level of theDRA234<7> may be received by the program output terminal FO2. In thethird decoder 413, the unit decoder corresponding to the decoded addressDA56<3> (e.g., including NMOS transistors N30 and N31) may be turned onor activated in response to the corresponding combination logic levels(e.g., A5 and A6), and the activated first logic level of the DRA56<3>may be transferred to program output terminal FO3.

In the above-described example method of FIG. 19, each of the outputsF01, F02 and F03 may transition to the first logic level. The outputsignals of the decoders 411/412/413 have may be received by thecombination circuit 500. The combination circuit 500 may perform an ANDoperation on the received signals to generate a redundancy enablessignal RENi at the first logic level.

In the example embodiment of FIG. 19, a redundancy operation may beformed by cutting a master fuse MF and control fuses other than fusesassociated with the defective address signal bits. The redundancy enablesignal RENi may be turned on or activated when a defective address maybe applied during normal operation of a semiconductor memory device(e.g., semiconductor device 1100), thereby debugging (e.g., correctingoperation) of the semiconductor device.

In another example embodiment of the present invention, instead of aone-to-one ratio between fuses and signal bit of a decoding row addressor decoding column address, a redundancy operation may be performedusing combinational logic. The redundancy enable signal may thereby begenerated at a higher speed. Further, a given number of fuses requiredmay be reduced. Further, a duration allocated to a redundancy operationmay be reduced (e.g., because a cutting time for given fuses in theredundancy operation may be reduced).

In another example embodiment of the present invention, a number offuses used for a redundancy operation may be reduced, which may therebyreduce a chip area for a semiconductor device, which may thereby reducea repair time for the semiconductor device.

Example embodiments of the present invention being thus described, itwill be obvious that the same may be varied in many ways. For example,while logic levels are above-described as transitioning to either thefirst or second logic level, it is understood that the first or secondlogic levels may be transitioned to or from either the first or secondlogic level. In other words, “transition” may not necessarily mean thata previous logic level differed from the logic level transitioned to.

Further, it is understood that the above-described first and secondlogic levels/states may correspond to a higher level (e.g., a logic “1”)and a lower logic level (e.g., a logic “0”), respectively, in an exampleembodiment of the present invention. Alternatively, the first and secondlogic levels/states may correspond to the lower logic level and thehigher logic level, respectively, in other example embodiments of thepresent invention.

Further, while above-described example circuits (e.g., row/column sparecircuits 10 a/11 a, etc.) include a given number of fuses, it isunderstood that other example embodiments of the present invention mayinclude any number of fuses (e.g., based on an internal/external,decoded/undecoded address length).

Further, while the AND gate/combination circuit 500 is above-describedand illustrated as an AND gate, it is understood that other exampleembodiments of the present invention may employ other types ofcombinational logic (e.g., a NOR gate, a NAND gate, etc.).

Such variations are not to be regarded as departure from the spirit andscope of example embodiments of the present invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

1. A redundancy program circuit, comprising: a master fuse circuitincluding a master fuse outputting an operation enable signal toindicate a master fuse operating status; at least one control fusecircuit including at least one control fuse, the at least one controlfuse circuit outputting an operating status signal for the at least onecontrol fuse; and a multiplexing unit configured to multiplex decodingaddress signal bits based on at least one of the operating status signaland the operation enable signal.
 2. The redundancy program circuit ofclaim 1, wherein: the operation enable signal indicates whether or notthe master fuse is cut, the at least one control fuse circuit includesat least two control fuses, the at least one control fuse circuitgenerating a plurality of control signal pairs as the operating statussignal, the plurality of control signal pairs indicating whether or nota corresponding control fuse is cut.
 3. The redundancy program circuitof claim 2, wherein: the multiplexing unit includes a first multiplexingcircuit and a second multiplexing circuit, wherein the firstmultiplexing circuit outputs logic levels indicative of half of signalbits of the decoding address signal bits to at least one output terminalin response to at least a portion of the plurality of control signalpairs; and the second multiplexing circuit reduces the half of signalbits received from the output terminals of the first multiplexingcircuit based at least in part on control signal pairs other than theportion of the plurality of control signal pairs received by the firstmultiplexing circuit when the operation enable signal is at a firstlogic level.
 4. The redundancy program circuit of claim 3, wherein theat least one control fuse circuit includes a given number of controlfuses based on the decoding address.
 5. The redundancy program circuitof claim 4, wherein the at least one control fuse includes two controlfuses when the signal bits of the decoding address number four bits andincludes three control fuses when the signal bits of the decodingaddress number eight bits.
 6. The redundancy program circuit of claim 3,wherein: the control fuse circuit is one of a plurality of control fusecircuits; the first multiplexing circuit is one of a plurality of firstmultiplexing circuits; the second multiplexing circuit is one of aplurality of second multiplexing circuits.
 7. The redundancy programcircuit of claim 1, further comprising: a gating circuit for performinga logical sum of logic levels of the multiplexed decoding address signalbits to generate a redundancy enable signal.
 8. The redundancy programcircuit of claim 1, wherein at least one of the multiplexed decodingaddress signal bits are associated with a defective memory cell.
 9. Theredundancy program circuit of claim 2, wherein: the master fuseoperating status indicates whether or not the master fuse is cut, thecontrol fuse circuit includes at least one control fuse, the controlfuse circuit generating at least one control signal pair as theoperating status signal, the at least one control signal pair indicatingwhether or not a corresponding control fuse is cut, the multiplexingunit includes a multiplexing circuit outputting a portion of the decodedaddress signal bits.
 10. The redundancy program circuit of claim 9,further comprising: a program fuse circuit for obtaining a given logiclevel from the outputted the portion of decoded address signal bits andoutputting one of signal among the outputted the portion of decodedaddress signal bits to a program output terminal in response to theoperation enable signal.
 11. The redundancy program circuit of claim 10,wherein a number of fuses included within the control fuse and theprogram fuse circuit is three when the bits of the decoding addressinclude four bits and the number of fuses included within the controlfuse and the program fuse circuit is five when the bits of the decodingaddress include eight bits.
 12. The redundancy program circuit of claim1, further comprising: a plurality of program fuse circuits, each of theplurality of program fuse circuits for obtaining a given logic levelfrom among bits of a decoding address, the bits of the decoding addressincluded among the multiplexed decoding address signal bits; a signalgeneration circuit for receiving a plurality of logic levels from theplurality of program fuse circuits, combining the received plurality oflogic levels and outputting the combined result as a redundancy enablesignal, wherein the at least one control fuse circuit includes aplurality of control fuse circuits, each of the plurality of controlfuse circuits having a control fuse generating a control signal pair asa status signal indicating an operating status of the control fuse, themultiplexing unit includes a plurality of multiplexing circuits, each ofthe plurality of multiplexing circuits outputting logic levelsindicative of less than all of the signal bits of the decoding address.13. The redundancy program circuit of claim 10, wherein: the operationenable signal indicates whether or not the master fuse is cut, the atleast one control fuse circuit includes at least two control fuses, thecontrol fuse circuit generating a plurality of control signal pairs asthe operating status signal, the plurality of control signal pairsindicating whether or not a corresponding control fuse is cut, and themultiplexing unit includes a first multiplexing circuit, a secondmultiplexing circuit and a third multiplexing circuit.
 14. Theredundancy program circuit of claim 13, further comprising: a pluralityof program fuse circuits, each of the plurality of program fuse circuitsoutputting a given logic level of one of a plurality of bits in adecoding address, the bits of the decoding address included among themultiplexed decoding address signal bits; and a signal generationcircuit for performing logical operation on the logic levels receivedfrom first and second program output terminals, and generating aredundancy enable signal based on the performed logical operation, 15.The redundancy program circuit of claim 13, wherein the secondmultiplexing circuit outputs logic levels of less than all of the signalbits in the decoding address applied in response to a correspondingcontrol signal pair among the plurality of control signal pairs and thethird multiplexing circuit reduces a number of the logic levels of theoutput terminals of the second multiplexing circuit until a single bitoutput is obtained in response to the control signal pairs other thanthe control signal pairs received by the first and second multiplexingcircuits and transfers the single bit to a program output terminal. 16.The redundancy program circuit of claim 13, wherein each of the first,second and third multiplexing circuits includes at least one NMOStransistor.
 17. The redundancy program circuit of claim 16, wherein theat least one NMOS transistor selectively transfers a logic level ofsignal bits applied to a drain terminal of the at least one NMOStransistor in response to a control signal pair received from acorresponding gate terminal of the at least one NMOS transistor.
 18. Theredundancy program circuit of claim 13, wherein: the control fusecircuit includes at least five control fuses and generates first,second, third, fourth and fifth control signal pairs as the operatingstatus signal indicating an operating status of corresponding controlfuses; the multiplexing unit further includes fourth and fifthmultiplexing circuits, the first and fifth multiplexing circuitsoutputting a logic level of a corresponding signal bit, thecorresponding signal bit included among the multiplexed decoding addresssignal bits applied in 4 bit units, to a corresponding first outputterminal, in response at least one of the first, second, third, fourthand fifth control signal pairs, the first and fifth multiplexingcircuits each having second output terminals independent from the firstoutput terminals; the program fuse circuit transfers the logic levels ofthe first output terminals corresponding to program output terminals,through each fuse connected corresponding to the first output terminalswhen the operation enable signal is activated and cuts each fuseconnected to corresponding second output terminals so that each of thesecond output terminals is not operationally connected to thecorresponding program output terminal; the second multiplexing circuitoutputs a logic level of a given signal bit among the multiplexeddecoding address signal bits applied in 8 bit units to a first outputterminal in response to the second control signal pair, the secondmultiplexing circuit having three output terminals independent from thefirst output terminal; the third multiplexing circuit outputs logiclevels of first, second, third and fourth output terminals of the secondmultiplexing circuit to first and second medium output terminals inresponse to the third control signal pair; and the fourth multiplexingcircuit transfers a logic level of the first medium output terminal to acorresponding program output terminal in response to the fourth controlsignal pair when the operation enable signal is activated anddisconnects the second medium output terminal from the correspondingprogram output terminal.
 19. The redundancy program circuit of claim 18,further comprising: a signal generation circuit for gating logic levelsof the program output terminals of the program fuse circuit and theprogram output terminals of the fourth multiplexing circuit andgenerating a redundancy enable signal.
 20. A redundancy program circuit,comprising: a master fuse circuit including a master fuse generating anoperation enable signal indicating an operating status of the masterfuse; a first fuse box circuit including first program fuses disposed soas to correspond to signal bits of a decoding address and generating afirst fuse box output signal in response to the operation enable signal;a second fuse box circuit including second program fuses disposed so asto correspond to signal bits of an internal address and generating asecond fuse box output signal in response to the operation enablesignal; and a gating circuit for gating the first and second fuse boxoutput signals and generating a redundancy enable signal.
 21. Theredundancy program circuit of claim 20, wherein the operating statusindicates whether or not the master fuse is cut.
 22. The redundancyprogram circuit of claim 20, wherein the redundancy enable signal isreceived by a redundancy row decoder or a redundancy column decoder. 23.The redundancy program circuit of claim 20, wherein the decoding addressis an address output from a predecoder and the internal address is anaddress received by the predecoder.
 24. A method of performing aredundancy program operation, comprising: generating an operation enablesignal; generating at least one control signal pair; selectivelyoutputting logic levels of at least a portion of a decoding addressbased at least in part on a first of the at least one control signalpair; and multiplexing the selectively outputted logic levels to attaina redundancy enable signal based at least in part on the at least onecontrol signal pair.
 25. The method of claim 24, wherein the redundancyenable signal is based on at least one control signal pair other thanthe first of the at least one control signal pair.
 26. The method ofclaim 24, wherein the multiplexing includes reducing signal bits of thedecoding, the reduced portion decoding address being the redundancyenable signal.
 27. The method of claim 24, wherein the at least onecontrol signal pair indicates an operating status of a correspondingcontrol fuse.
 28. A method of performing a redundancy program operation,comprising: generating an operation enable signal; generating a firstfuse box output signal based on whether the operation enable signal isactivated; generating a second fuse box output signal at a program fusedisposed so as to correspond to signal bits of an internal addressgenerated before an applied external address is decoded; and gating thefirst and second fuse box output signals to generate a redundancy enablesignal.
 29. A method of reducing the number of fuses used for aredundancy program operation, comprising: allocating a first portion offuses corresponding to signal bits of a decoding address; and allocatinga second portion of fuses corresponding to signal bits of an internaladdress.
 30. The method of claim 29, wherein the internal address isgenerated before predecoding an external address.
 31. A redundancyprogram circuit, comprising: a master fuse circuit including a masterfuse outputting an operation enable signal to indicate a master fuseoperating status; at least one control fuse circuit including at leastone control fuse, the at least one control fuse circuit outputting anoperating status signal for the at least one control fuse in response tothe operation enable signal; and a decoding circuit for decoding signalbits of a decoding address in response to the operating status signaland transferring a given logic level along with the decoding address toa decoding output terminal.
 32. The redundancy program circuit of claim31, wherein the decoding address is decoded from one of an internaladdress generated before predecoding and an external address receivedfrom an external device.
 33. The redundancy program circuit of claim 31,wherein the decoding circuit includes a plurality of decoders, a numberof the plurality of decoders corresponding to a number of signal bits inthe decoding address.
 34. The redundancy program circuit of claim 33,wherein each of the plurality of decoders includes at least one NMOStransistor.
 35. The redundancy program circuit of claim 34, wherein theat least one NMOS transistor for each of the plurality of decodersincludes channels connected in series.
 36. The redundancy programcircuit of claim 31, wherein: the at least one control fuse circuitincludes a plurality of control fuse circuits which are controlled inresponse to the operation enable signal of the master fuse circuit, theat plurality of control fuse circuits including a number of controlfuses corresponding to a number of decoding address signal bits of thedecoding address; and the decoding circuit is one of a plurality ofdecoding circuits, each of the plurality of decoding circuits outputtingthe given logic level to a corresponding output terminal.
 37. Theredundancy program circuit of claim 36, further comprising: acombination circuit for gating the logic levels received from theplurality of decoding circuits at the corresponding output terminals andgenerating a redundancy enable signal as a result of the gatingoperation.
 38. The redundancy program circuit of claim 36, wherein thenumber of control fuses within the plurality of control fuse circuitsequals the number of decoding address signal bits of the decodingaddress
 39. The redundancy program circuit of claim 37, wherein theoperating status signal includes three control signal pairs when thedecoding address includes eight signal bits.
 40. The redundancy programcircuit of claim 39, wherein the eight signal bits of the decodingaddress are decoded by eight combinational logic inputs generated basedon the three control signal pairs.
 41. The redundancy program circuit ofclaim 37, wherein the combination circuit includes an AND gate.
 42. Amethod of performing a redundancy program operation, comprising:generating an operation enable signal; generating an operating statussignal indicating a status of at least one control fuse; and decodingsignal bits of a decoding address in response to the operating statussignal and transferring a given logic level associated with a defectivememory cell along with the decoding address to a decoding outputterminal.